[TowerTalk] 18AVT DC short?

[n0tt1 at juno.com]

Pete,

There's a small plastic spool with wire wrapped around
it that forms the RF choke on the HF bands.   I'm pretty
sure it's also a "matching" coil since the reactance will
vary band-to-band.  

If something happens to that coil or its connections, 
it is potted in bee's wax that can be removed (melted out) 
with a soldering gun (with a long homebrew tip on it) or 
possible a heat gun if the temperature can be controlled.

I *think* I have more details about that "choke" if you
need to know....wire size, number of turns, etc.

I modified my 18AVT for portable use and I use it on
just about every Field Day....fits in a ~3-ft canvas bag
with coax, tripod stand, tools, etc.

73,
Charlie, N0TT

On Mon, 10 Mar 2014 12:13:46 -0400 Pete Smith N4ZR <n4zr at contesting.com>
writes:
> I recently bought a very old 18AVT-WB which, after working for a 
> while, 
> is no longer resonant on any band, or even close.
> 
> Brought the base section into the house, and it appears to have a DC 
> 
> short from center to outer conductor of the SO-239, but when I test 
> with 
> MY MFJ-259B, the short is not present at RF.
> 
> Can anyone tell me if, as it appears, this vertical has an RF choke 
> 
> inside the molded plastic base shunting the output for lightning?
> 
> -- 
> 73, Pete N4ZR
> Check out the Reverse Beacon Network at
> http://reversebeacon.net,
> blog at reversebeacon.blogspot.com.
> For spots, please go to your favorite
> ARC V6 or VE7CC DX cluster node.
> 
> _______________________________________________
> 
> 
> 
> _______________________________________________
> TowerTalk mailing list
> TowerTalk at contesting.com
> http://lists.contesting.com/mailman/listinfo/towertalk
>